package entity;public class User {private String userID;private String username;private String userword;public String getUserID() {return userID;}public void setUserID(String userID) {this.userID = userID;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getUserword() {return userword;}public void setUserword(String userword) {this.userword = userword;}}

package dao;import java.util.*;
import java.sql.*;import entity.*;
import DBHelper.*;public class Userdao {public List getAllUser() {String SQL = "SELECT * FROM user";ResultSet rs = DBHelper.getResultSet(SQL);return tools.ResultSettoList(rs, User.class);// try{// String SQL="SELECT*FROM user";// ResultSet rs= DBHelper.getResultSet(SQL);// List users=new ArrayList();// while(rs.next())// {// User u=new User();// u.setUserID(rs.getString("userID"));// u.setUsername(rs.getString("userName"));// u.setUserword(rs.getString("password"));// users.add(u);// }// return users;// }catch(Exception ex){return null;// }//}public boolean insert(User u){String SQL="INSERT INTO user(userID,username,userword) VALUES(?,?,?)";Object[] params=new Object[]{u.getUserID(),u.getUsername(),u.getUserword()};int n=DBHelper.ExecSql(SQL,params);if(n>0) return true;else return false;}public boolean update(User u){String sql="update  user set username=?,userword=? where userID=?";Object[] obj=new Object[]{u.getUsername(),u.getUserword(),u.getUserID()};int rs=DBHelper.ExecSql(sql,obj);if(rs==1)return true;elsereturn false;}public boolean delete(User u){String sql="delete from user where userID=?";Object[] obj=new Object[]{u.getUserID()};int rs=DBHelper.ExecSql(sql,obj);if(rs==1)return true;elsereturn true;}}

package dao;import java.sql.SQLException;
import java.util.List;import entity.User;public class testDAO {public static void main(String[] args) throws SQLException {
//       TODO Auto-generated method stub
//      测试查询
//     Userdao dao= new Userdao();
//     List list =dao.getAllUser();
//     System.out.println(list.size());
//      测试添加：Userdao dao=new Userdao();User u= new User();
//         u.setUserID("d");
//         u.setUsername("d");
//         u.setUserword("d");
//          dao.insert(u);
//
//         测试删除：
//         u.setUserID("d");
//         dao.delete(u);
//         System.out.println("u");
//         测试修改u.setUserID("c");u.setUserword("q");u.setUsername("q");dao.update(u);System.out.println("u");}}

package servlet;import java.io.*;
import java.util.*;import javax.servlet.*;
import javax.servlet.http.*;import dao.*;
import entity.*;
import DBHelper.*;
public class Userservlet extends HttpServlet {/*** Constructor of the object.*/public Userservlet() {super();}/*** Destruction of the servlet. <br>*/public void destroy() {super.destroy(); // Just puts "destroy" string in log// Put your code here}/*** The doGet method of the servlet. <br>** This method is called when a form has its tag value method equals to get.* * @param request the request send by the client to the server* @param response the response send by the server to the client* @throws ServletException if an error occurred* @throws IOException if an error occurred*/public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request, response);}/*** The doPost method of the servlet. <br>** This method is called when a form has its tag value method equals to post.* * @param request the request send by the client to the server* @param response the response send by the server to the client* @throws ServletException if an error occurred* @throws IOException if an error occurred*/public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {Userdao dao=new Userdao();List users=dao.getAllUser();request.getSession().setAttribute("users", users);response.sendRedirect("show.jsp");}/*** Initialization of the servlet. <br>** @throws ServletException if an error occurs*/public void init() throws ServletException {// Put your code here}}

<%@ page language="java" import="java.util.*,dao.*,DBHelper.*,entity.*"  pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><title>User.jsp</title></head><body><%List<User>users = (List<User>)session.getAttribute("users");
//String uid=request.getParameter("userID");//String uname=request.getParameter("username");
//String password=request.getParameter("password");
//out.print("用户ID:"+uid+"<hr/>");
//out.print("姓名:"+uname+"<hr/>");
//out.print("密码:"+password+"<hr/>");out.print("<table border=1 cellspacing=1>");out.print("<tr><td>id</td><td>用户名</td><td>密码</td></tr>");for(User u:users){out.print("<tr>");out.print("<td>"+u.getUserID()+"</td>");out.print("<td>"+u.getUsername()+"</td>");out.print("<td>"+u.getUserword()+"</td>");out.print("</tr>");}out.print("</table>");%></body>
</html>